35 U.S.C. § 101 - INVENTIONS PATENTABLE
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
(Public Law 112-29, sec. 33, 125 Stat. 284 (Sept. 16, 2011) provided a limitation on the issuance of patents (see AIA § 33 ).)